dca: extract core substream's embedded downmix coeffcient codes, if present.

As per ETSI TS 102 114 V1.4.1 specification.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
dca: improve default stereo downmix coefficients.

Previous coefficients were producing a non-normalized, incorrect Lt/Rt downmix.

The new coefficients produce a standard Lo/Ro downmix with 3dB attenuation.

This should match the typical default coefficients used by DTS encoders.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
dca: support mixing LFE in dca_downmix.

Embedded downmix coefficients can use this.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
dcadec: treat all 2-channel modes as Stereo in dca_downmix.

The check for (prim_channels > 2) before calling dca_downmix made these
cases unreachable, but now 2.1 layouts will go through the downmix code.
Having dual mono, Lt/Rt and sum-difference layouts print errors when
regular Stereo doesn't seems pointless.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
dcadec: add disable_xch private option.

This supplements the deprecated request_channels-based control of XCh decoding.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
Merge commit '44b17d794aa508ae21f438ae80bfe8aaf4b426e1'

* commit '44b17d794aa508ae21f438ae80bfe8aaf4b426e1':
  dca: extract core substream's embedded downmix coeffcient codes, if present.

Conflicts:
	libavcodec/dcadata.h
	libavcodec/dcadec.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/dcadec: print more details about errors

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '149438cfe5d233c46bb18341b7c574fe643dd5f2'

* commit '149438cfe5d233c46bb18341b7c574fe643dd5f2':
  dca: improve default stereo downmix coefficients.

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'aaa44d0299338e3bc90128816c21dbfab06cdb48'

* commit 'aaa44d0299338e3bc90128816c21dbfab06cdb48':
  dca: support mixing LFE in dca_downmix.

Conflicts:
	libavcodec/dcadec.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '220494ad0b2e9e980ef703b46b69308236f29be5'

* commit '220494ad0b2e9e980ef703b46b69308236f29be5':
  dcadec: treat all 2-channel modes as Stereo in dca_downmix.

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge remote-tracking branch 'qatar/master'

* qatar/master:
  dcadec: add disable_xch private option.

Conflicts:
	libavcodec/dcadec.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/dcadec: AVClass is const

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/dcadec: set  AV_CLASS_CATEGORY

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
ffserver: extend feedback in http_start_receive_data()
ffserver: deprecate inconsistent parsing behavior of Truncate option

Also make it accept the more consistent behavior (boolean option set to
true when specified).
doc/ffserver: extend documentation for various file-related options
doc/ffserver: reorder encoding options, and mark them as such

Also add notice about ffmpeg -override_ffserver option.
doc/ffserver: uncomment line in stream section example
doc/ffserver: extend documentation for Feed/File stream options
doc/ffserver: fix RTSPOtion tpo

Spotted-by: ubitux